What’s the magic number for Senate Democrats on election night?

According to Democratic Senatorial Campaign Committee Chairman Charles Schumer (N.Y.), it doesn’t necessarily need to be the filibuster-proof 60 seats that Democrats are striving to win on Nov. 4.

Schumer and National Republican Senatorial Committee Chairman John Ensign (Nev.) sparred publicly at the National Press Club Tuesday. At the biennial panel, Schumer recalled how even just that morning it was suggested to him that Democrats might be disappointed if they only win six seats this cycle — three short of a Senate Democratic caucus of 60.

“Fifty-seven seats?” Schumer scoffed. “We haven’t had that since 1979. So we’re feeling very good that we’re going to pick up a successful amount, a large number of seats, and have a successful election. As for 60, it is possible. You can look at the map yourself. But given the red terrain we’re fighting in, it’s very difficult.”

To reach 60 seats, Schumer said Democrats would have to win in traditionally Republican states, like Georgia and Mississippi, that have come on the competitive radar in recent weeks.

In his remarks to the crowd, Ensign not only warned about Democrats reaching 60 seats, but also what might happen if Democrats get close enough to a filibuster-proof majority that they only need to recruit a couple Republicans for certain votes.

“The big question on everyone’s mind is are the Democrats going to get to 60?” Ensign said. “Are we going to be able to hold a filibuster-proof Senate? And it’s not even the 60 number that is the magic number, I would think. I think that if the Democrats get to 57 or 58, on a lot of issues, they will get an overriding Senate filibuster.”

The Republican campaign chief acknowledged that while his party always expected to lose seats this cycle, the recent economic crisis did not help his candidates in the waning weeks of campaign season. Voters still blame Republicans for their financial woes, he said, even though they are not in power on Capitol Hill anymore.

“We’re dealing with an unpopular president, we have a financial crisis, we have a country who thinks that not only Republicans hold the White House, but half the country still thinks that Republicans are in charge of the House and Senate,” Ensign said.

The result is a more competitive electoral map. Ensign said that though he expected not to have to play in traditionally southern states like Mississippi, Kentucky and Georgia, he was confident his party would hold onto those seats. And contrary to published reports earlier this week, the NRSC will continue to play in its single pickup opportunity this cycle: Sen. Mary Landrieu’s (D) seat in Louisiana.

Ensign said the NRSC would also continue to play until Election Day in the open-seat race in Colorado, where former Rep. Bob Schaffer (R) continues to trail Rep. Mark Udall (D) by single digits in polls but outside of the margin of error.

Breaking away from Senate seat math, the discussion quickly turned to just how liberal the freshman class of Democrats — and therefore the entire Senate — could be in January if Democrats meet expectations in November.

“In 2006, the Democrats put more conservative-type Democrats up,” Ensign said. “In this past cycle, if you look at the crop of candidates, it’s about as far left a group of candidates as we’ve seen in a long time.”

Ensign called out Democratic Senate candidates like comedian Al Franken, running against Sen. Norm Coleman (R-Minn.), and state Speaker Jeff Merkley (D), running against Sen. Gordon Smith (R-Ore.), as two “pretty far left” candidates who happen to be running in a good year for Democrats.

Schumer, however, rebuffed Ensign’s argument, instead citing candidates like former Virginia Gov. Mark Warner (D), who is expected to win the Senate seat currently held by retiring Sen. John Warner (R-Va.). Instead, Schumer argued that in recruiting, “mainstream candidates make the best Senate winners.”

“We have great candidates,” Schumer said. “They are thoughtful, they are moderate and, I don’t agree with John on this: These candidates, should they come to the U.S. Senate, will strengthen the moderate wing of the Democratic Party.”